I have played around with some IPv6 policies and teredo options, so it might be that I set some options around that, or I must have disabled something.Otherwise maybe the recent installations of VPN clients and Packet sniffers must have done this.

Generally under windows I find you have to delete the interface and basically "re-do" it.

netsh int ipv6 delete interface IP6Tunnel

That should get rid of the interface, associated addresses and routes.

Then do the creation commands again and it should work.

EDIT: OK I looked at your message closer and I see now that it looks like it's not creating the 6in4 interface. Not sure what's going on here. Maybe the VPN client screwed up ipv6? You may want to do "netsh int ipv6 install" again or something like that.

The problem is that when I try to create the tunnel IP6Tunnel then it creates something called "Local Area Connection* 27" rather then IP6Tunnel.

Yeh I edited my response above. Looks like windows is hosed up or something. Not sure what to do here. Maybe try "netsh int ipv6 uninstall" then "netsh int ipv6 install" or something. Or try a different interface name just to see if it will create the tunnel vnic.

Which VPN client? You could always try uninstalling it and see if it works again.

EDIT: I notice now that you said it was Win7. So yeah.

You could also try to do the ipv6 reset command and see if that changes anything. At this point it looks like a "Windows issue". I'm not really that deeply familiar with Win7, so maybe someone here that has it can help.

But by now I have disabled them all and the tunneling still doesn't work.

Well, on XP at least, WinPcap doesn't hurt IPv6. I doubt the other applications would either.

The Cisco VPN client is the most likely culprit. Disabling them doesn't mean deinstalling them. Unless you mean deinstalling.

Another thing you might try is to go into some control panel and disable ipv6, hit OK, then go back in and enable it again. Sometimes windows needs to be "nudged" when config changes are made (as the VPN client probably dorked around with the network stack a lot).

I've tried the ipv6 reset and that didn't help. Also I've tried to disable IPv6 restart and enable it again, but that did not help either.

I don't know if it is because of these programs, those are just the programs I have installed after I had IPv6 working, and now it's not working.I also changed some policies and registry entries but I think I have reverted them all now.

So I really don't know what I did so that it is not working by now :-/.

I will try do deinstall Cisco VPN Client but It might be that I've installed that just before I've tried the IPv6 stuff, so maybe that's not the problem.

Yeah as I said, the VPN client would be the most likely, since it would do the most changes to the network stack on the computer, installing likely a virtual NIC and some other stuff that it'd shim into the proto stack.

May want to google around and see if you can find out if this is a known issue.

Second most likely is winpcap, since that also puts something into the network stack, but as I said, under XP it doesn't do any harm, but YMMV since you're using win7 which is still a new OS that developers aren't as familiar with, etc.